7,055 research outputs found
CP Tagged Decays at SuperBaBar
We explore the possibility of measuring the CKM parameter gamma using CP
tagged decays at a very high luminosity e+e- B Factory. A new collider capable
of integrating as much as 10 inverse attobarns per year is being discussed as a
possible future for SLAC beyond the current PEP-II program, and could also be
in the future of KEK. In two years of operation, it could be possible for a
successor to BaBar or Belle to accumulate a sample of one million CP tagged B
decays. We find that a theoretically clean extraction of gamma with uncertainty
less than 5 degrees may be achievable in the analysis of such a data set.Comment: 14 pages, 4 figures; minimal revisions for version to appear in
Physical Review D, all formulas and conclusions unchange
Chromosome mapping: radiation hybrid data and stochastic spin models
This work approaches human chromosome mapping by developing algorithms for
ordering markers associated with radiation hybrid data. Motivated by recent
work of Boehnke et al. [1], we formulate the ordering problem by developing
stochastic spin models to search for minimum-break marker configurations. As a
particular application, the methods developed are applied to 14 human
chromosome-21 markers tested by Cox et al. [2]. The methods generate
configurations consistent with the best found by others. Additionally, we find
that the set of low-lying configurations is described by a Markov-like ordering
probability distribution. The distribution displays cluster correlations
reflecting closely linked loci.Comment: 26 Pages, uuencoded LaTex, Submitted to Phys. Rev. E,
[email protected], [email protected]
Excited Heavy Mesons Beyond Leading Order in the Heavy Quark Expansion
We examine the decays of excited heavy mesons, including the leading power
corrections to the heavy quark limit. We find a new and natural explanation for
the large deviation of the width of the from the heavy quark
symmetry prediction. Our formalism leads to detailed predictions for the
properties of the excited bottom mesons, some of which recently have been
observed. Finally, we present a detailed analysis of the effect of power
corrections and finite meson widths on the angular distributions which may be
measured in heavy meson decays.Comment: Uses REVTeX, 19 pages, 6 EPS figures embedded with epsf.st
A relativistic chiral quark model for pseudoscalar emission from heavy mesons
The amplitudes for one-pion mediated transitions between heavy meson excited
states are obtained in the framework of the relativistic chiral quark model.
The effective coupling constants to pions and the decay widths of excited heavy
mesons with l<=2 for non-radially excited, and the l=0 radially excited mesons
are presented for both charmed and beauty mesons. We also discuss the allowed
decays of strange excited heavy mesons by emission of a K-meson.Comment: 20 pages, revte
The Origin of a Repose Angle: Kinetics of Rearrangements for Granular Materials
A microstructural theory of dense granular materials is presented, based on
two main ideas. Firstly, that macroscopic shear results form activated local
rearrangements at a mesoscopic scale. Secondly, that the update frequency of
microscopic processes is determined by granular temperature. In a shear cell,
the resulting constitutive equations account for Bagnold's scaling and for the
existence of a Coulomb criterion of yield. In the case of a granular flow down
an inclined plane, they account for the rheology observed in recent experiments
and for the temperature and velocity profiles measured numerically.Comment: submitted to PR
Hadronic Transitions among Quarkonium States in a Soft-Exchange-Approximation. Chiral Breaking and Spin Symmetry Breaking Processes
Although no asymptotic heavy quark spin symmetry, and even more no flavor
symmetry, are expected for systems such as quarkonium, a numerical discussion
shows that for some processes and in a preasymptotic region which may roughly
include charmonium and bottomonium, the use of the spin-symmetry may be useful
in conjunction with chiral symmetry for light hadrons (soft-exchange-
approximation regime, SEA). We continue our discussion of hadronic transitions
in the SEA-regime by studying in particular chiral breaking transitions such as
, , level splittings and transitions which break
both chiral and spin symmetry, such as , , and .Comment: LaTeX (style article) 19 pages, UGVA-DPT 12-80
Crack fronts and damage in glass at the nanometer scale
We have studied the low speed fracture regime for different glassy materials
with variable but controlled length scales of heterogeneity in a carefully
mastered surrounding atmosphere. By using optical and atomic force microscopy
(AFM) techniques we tracked in real-time the crack tip propagation at the
nanometer scale on a wide velocity range (mm/s - pm/s and below). The influence
of the heterogeneities on this velocity is presented and discussed. Our
experiments reveal also -for the first time- that the crack progresses through
nucleation, growth and coalescence of nanometric damage cavities within the
amorphous phase. This may explain the large fluctuations observed in the crack
tip velocities for the smallest values. This behaviour is very similar to what
is involved, at the micrometric scale, in ductile fracture. The only difference
is very likely due to the related length scales (nanometric instead of
micrometric). Consequences of such a nano-ductile fracture mode observed at a
temperature far below the glass transition temperature in glass is finally
discussed.Comment: 12 pages, 8 figures, submitted to Journal of Physics: Condensed
Matter; Invited talk at Glass and Optical Materials Division Fall 2002
Meeting, Pittsburgh, Pa, US
LICOR-Liquid Columns' Resonances
The aim of the experiment LICOR was the investigation of the axial resonances oi cylindrical liquid columns supported by equal circular coaxiaJ disks. In preparation ot the D-2 experiment a •heoreiical model has been developed, which exactly describes the small amplitude oscillations of finite cylindrical columns between coaxial circular disks. In addition, in terrestrial experiments the resonance frequencies of small liquid columns with up to 5 mm in diameter have been determined and investigations with density-matched liquids (silicon oil in a waierlmethanol mixture) have been performed. For the D-2 experiment LICOR the front disk and the rear disk lor use in the AFPM have been constructed and equipped with pressure sensors and the necessary electronics. The pressure exerted by the oscillating liquid column on trie supporting disks vsas as low as 10 Pa. Since the data downlink of the Materials Research Laboratory was just one signal oer second and channel, it was necessary to determine amplitude and phase of the pressure already in the LICOR disks. The D-2 experiment has been successfully performed. It has fully confirmed the theoretical models and remarkably supplements the experiments on small liquid columns and on density-matched columns
Bargaining and reputation: an experiment on bargaining in the presence of behavioural types
We conduct a series of laboratory experiments to understand what role commitment and reputation play in bargaining. The experiments implement the Abreu and Gul (2000) bargaining model that demonstrates how introducing behavioral types, which are obstinate in their demands, creates incentives for all players to build reputations for being hard bargainers. The data are qualitatively consistent with the theory, as subjects mimic induced types. Furthermore, we find evidence for the presence of complementary types, whose initial demands acquiesce to induced behavioural demands. However, there are quantitative deviations from the theory: subjects make aggressive demands too often and participate in longer conflicts before reaching agreements. Overall, the results suggest that the Abreu and Gul (2000) model can be used to gain insights to bargaining behavior, particularly in environments where the process underlying obstinate play is well established
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